Mud degasser



1959 I R. w. ERWIN 2,869,673

MUD DEGASSER Filed Jan. 25, 1955 2 Sheets-Sheet l lnvenTor: Ransome w. Erwin R. w. ERWIN Jan. 20, 1959 MUD DEGASSER 2 Sheets-Sheet 2 Filed Jan. 25, 1955 MUD DEGASSER Ransome W. Erwin, Fort Worth, Tex., assignor to Salt vgater Control, line, Fort Worth, Tex., a corporation Texas Application January 25. 1955, Serial No. 483,944

12 Claims. (Cl. 183-25) This invention relates to new and useful improvements and structural refinements in drilling mud de-gassers for oil wells and is a continuationin-part of my earlier patent application Serial No. 296,396, filed June 30, 1952, now Patent No. 2,748,884, dated June 5, 1956, in which the mud degasser system as a whole is disclosed and broadly claimed.

The claims of the present application are directed to the vacuum degasser tank per se and to improvements in the degasser system over what is disclosed and claimed in my aforesaid application.

An object of the present invention is to substantially simplify and render more eflicient the de-gassing apparatus disclosed in my earlier application, some of the more important features of the present disclosure being the provision of an elongated sump with a sloping bottom at the underside of the de-gasser tank, which sump permits the apparatus to be mounted in its conventional level position but effectively safeguards against sediment dropping out of the drilling mud passing through the tank. Moreover, the provision of the sump facilitates the use of mud outlet pipes at both sides as well as at the end or bottom of the tank and reduces the need for washing out the tank to a minimum.

Another feature of the instant invention involves the provision of removable washing nozzles using mud from a pressure source to flush cuttings or sediments from the sump and from the inside of the mud overflow pipe while the de-gasser is in operation.

A further feature of this invention is to provide a throttle valve in the mud intake pipe in order to increase the vacuum in the degasser tank beyond what is normally obtainable when lifting the mud from its level, the throttle valve being hand set and, therefore, capable of proper adjustment in accordance with operating conditions.

A still further feature of this invention resides in the provision of a float for controlling the outlet of mud from the tank, which eliminates necessity for the U- shaped liquid seal discharge shown in my earlier patent.

Other features of the invention will be apparent from the following detailed description and the accompanying drawings in which a specific embodiment of the invention is set forth by way of illustration rather than by way of limitation.

In the drawings:

Figure 1 is a side elevational view of the de-gasser apparatus, certain portions thereof being shown in section;

Figure 2 is a cross-sectional view on an enlarged scale, taken substantially in the plane of the line 22 in Figure 1;

Figure 3 is a fragmentary perspective view showing the arrangement of the mud overflow pipe, cascade plates and Wash pipes;

Figure 4 is a longitudinal sectional view of one of the washing nozzles;

Figure 5 is a fragmentary side elevational view, partly States Patent in section, illustrating a modified form of the invention;

and

Figure 6 is a fragmentary plan view of the mud outlet in the bottom of the sump shown in Figure 5.

With reference now to the accompanying drawings in detail, the de-gasser apparatus, as in my earlier application, comprises a horizontally elongated tank 10 provided at least at one end thereof with a removable cap or cover 11 through which extends a flanged adapter 12 interposed between the mud intake pipe 13 and the open topped overflow pipe or trough 14. The latter is disposed in the upper portion of the-tank 10 and is similar in construction to that disclosed in my earlier application. In order to provide more even distribution of mud throughout the length of overflow pipe 14, the top portion of the pipe or trough 14 is cut out to form a tapered opening, as shown in Figure 3, with the narrow portion at the inlet end, gradually becoming wider at the opposite end.

In place of the three pairs of cascade plates PI'O. vided in my previous apparatus, the tank 10 contains only one pair of such cascading plates, indicated at 15, these extending downwardly and outwardly from the overflow pipe 14 toward the opposite sides of the tank, as is best shown in Figure 2.

The tank 10 is equipped at the bottom thereof with a longitudinally extending sump 16 having a bottom wall 17 which slopes gradually downwardly from the inlet to the outlet end of the tank. Thus, the sump 16 permits location of the tank in a level position, but nevertheless affords a slope which safeguards against sediment dropping out from the mud passing through the tank. Moreover, the sump 16. permits mud outlets 18 to be located at the sides of the same, as well as at the end thereof indicated at 19, or at the bottom thereof indicated at 20, the latter being hereinafter more particularly referred to. The sloping bottom 17 of the sump 16 per mits the apparatus to be operated for several days without washing, while the tank shown in my earlier application required washing every twenty-four hours.

Along the lines of my earlier invention, the singleoutlet 19 or multiple outlets 18, 19 communicate with a U-shaped liquid seal discharge 21 provided with a ceramic lined jet 22 connected to a pressured mud supply from a conditioner circulating pump as set forth in my Patent No. 2,748,884, dated June 5, 1956. The discharge 21 then enters a sand .trap or second mud tank 23, a wear plate 24 being provided at the end of the discharge, as shown. The U-shaped discharge and the second mud tank are equipped with drain valves 25, 26, respectively, while the flow of mud to the jet 22 is controlled by a valve 27. The function of the jet 22 is the same as that of the jet 38 of my Patent No. 2,748,884, namely to cause the mud being treated to flow into, through and out of the tie-gassing tank.

Also as in my earlier application, all gases removed from the mud pass through a pick-up pipe 28 beneath the trough 14, saidpipe having a valve 29 thereon actuated by a float 3t) buoyant on the level 31 of the dc-gassed mud in the tank 10. In this connection it is to be noted that as the mud flows over the cascade plates 15 as indicated at 32 during the de-gassing opera tion, it gravitates to the side walls of the tank 1.0 as indicated at 33 in Figure 2 and thence to the sump 16. After passing through the valve 29, the gases picked up by the pipe 28 travel through a line .34 into a conventional float actuated liquid trap 35 and through a vacuum pump 36, from which they are discharged by an outlet 37. The pump 36, a motor 38 for driving the same and the trap 35 may be mounted upon a suitable platform 39 on top of the tank 10. A sight glass 4.0.

Patented Jan. 20, 1959 a vacuum regulator 41 and a control valve 42 are preferably provided in the line .34, as shown.

In common with my earlier application, the means for washing the interior 'of the de-gasser tank comprise a" pair of perforated wash pipes 43 located in the upper portion of the tank above and at opposite sides of the overflow pipe 14 and apair of similar pipes 44 disposed adjacent the lower edges of the cascade plates 15. The pipes 43, 44 are fed with water under pressure from a suitable pipe line 45, the latter'being provided with a connection 46through which suitable 'mud conditioning chemicals may be introduced into the system for thorough mixing with mud being de-gassed. yln addition to the water washing facilities above described. flushing jets 47, 48 are provided in the opposite ends' of the tank 10, the jet 47 being located near the bottom of the tank and directed obliquely into the sump 16 while the jet 48 is located near the top of the tank and directed axially into the overflow pipe or conduit 14. The jets 47, 48 are adapted for connection to a Supply of mud and periodic flushing through these jets may be undertaken while the apparatus is in operation, thus minimizing the need for water washing and avoiding dilution of the mud in the tank by water. As is bestshown in Figure 4, the jets 47, 48 are mounted in the ends of the tank through screw-threaded sleeves 49, whereby the jets may be readily removed for purposes of inspection or cleaning. Each jet is connected to its mud supply line 50 by a separable coupling 50', and a valve 51 is also provided for controlling the flow of r'nud through each of the two jets. The aforementioned mud intake pipe 13 is provided with a hand set throttle valve 52 and has its intake end in communication with an initial mud receptacle or sump 53 which, in turn, receives mud from the drilling well head through a pipe 54. The sump 53 is equipped with a drain valve 55 and as an accessory to the de-gasser, a choke mud gas separator 56 may be installed in the sump 53. If a well is kicking and is flowed therefrom through choke lines 101, 102 and 103 into the separator 56 from a blowout preventer (not shown), often so much gas is produced that conventional means will not save the mud from being sprayed and lost. Also, the gas itself can be a fire hazard. The open-bottomed separator 56 effectively separates the gas and mud, allowing the gas to be vented at a safe distance from the rig and drops the mud into the sump 53 where it may then be picked up by the de-gasser and completely denuded of gas by the vacuum treatment.

As in my earlier application, the tank is mounted on suitable supports 57 and extends longitudinally above the -mud trough 58 and if for any reason the degasser fails to pick up any or all of the mud in the sump 53, the mud will automatically overflow the sump and pursue its course down the trough as if the de-gasser equipment were not provided. Finally, it will be noted that the aforementioned trap 35 is provided with a suitable drain 59, as shown.

Operation When the apparatus is in normal operation, gas cut mud from the well head pipe 54 will flow into the sump or initial receptacle 53 as indicated at 60. The mud will then be picked up by the intake pipe 13 and flow into the pipe 14 inside the degasser tank 10. The mud overflowing from the pipe 14 will then cascade over the plates as indicated at 32 and the high vacuum in the tank 10 will effectively withdraw all gases from the mud. These gases, in turn, will be picked up by the pipe 28, while the de-gassed mud will gravitate along the sides of the vacuum tank to the sump. 16 and will then be drawn through the U-tube 21 by the action of the jet 22 into the outlet tank or receptacle 23 communicating with the mud trough 58, from which the de-gassed mud is returned to the well by means of a suitable pump as set forth in my Patent No. 2,748,884, dated June 5, 1956.

If a well is kicking, mud from the well, after passing through a blowout preventer, is flowed through one or more of the valved choke? lines 100, 101, 102 into the emergency or choke mud gas receptacle 56, wherein excess gas is removed from the mud and passed out through gas vent at the top of the separator, while the mud from which the excess gas has been separated drops into the initial mud receiving tank, sump or recep' tacle 53 to be passed into the main degasser vacuum tank 10 through the valved intake pipe 13 to be further treated for removal of gas from the mud as described above.

The throttle valve 52 in the intake pipe 13, being set by hand, requires no complicated regulators or auto matic devices and increases vacuum in the de-gasser tank to beyond what is normally obtainable when lifting mud from its level to the de-gasser. Often, depending on the weight of the-mud, only five to seven inches of mercury vacuum are required to pull the total mud circulation into the de-gasser. If more vacuum is required, in order to properly denude the mud of gas, the valve 52 may be throttled, necessitating more vacuum to lift the mud into the de-gasser. In this manner, as much as twenty-four inches of mercury vacuum may be applied for de-gassing the mud, without undue elevation at the de-gasser above the mud source level. If the mud level pulls dry to inlet, air enters with the mud, causing no harm.

The flushing jets 47, 48 maybe used periodically while the apparatus is in operation, these jets, as already explained, using mud from a pressurized source to flush cuttings or sediments from the sump 16 and from the inside of the overflow pipe 14. The use of mud for this purpose prevents dilution of the mud in the tank with water, and the sediments may be flushed out quickly, Without shutting down or draining the de-gasser. The jets may be readily removed for purposes of cleaning or inspection.

It is preferred that the de-gasser tank be coated both inside and out with a baked on, caustic resistant plastic, which will discourage any tendency of the mud caking or building up on exposed surfaces. Moreover, the smooth texture of such plastic finish will materially facilitate the washing down of the tank with water from .the wash pipes 43, 44, and the plastic coating on the With reference now to the accompanying Figures 5 and 6 which show a modified form of the invention, the mud outlet 20 in the bottom wall 17 of the tank sump 16 is provided with a second float 61 which is disposed below the aforementioned float 30 and is attached to a pivoted arm 62 provided with a hand lever 63 at the outside of the tank. The float 61 is prevented from completely closing the outlet 20 by a plurality of spaced, upwardly projecting seats 64 located around the periphery of the outlet, as is best shown in Figure 6. In this arrangement of the invention the U-shaped liquid seal discharge 21 is eliminated and the outlet 20 is connected by a discharge pipe 65 with the aforementioned tank 23, the pipe 65 being equipped with the ceramics lined jet 22. Y The float 30 is operatively connected by the linkage 66 to the aforementioned gas outlet control valve 29 and when the mud level 31 in the tank rises, the valve 29 is closed, thus diminishing vacuum on the gas outlet 28 and allowing the mud level to be pulled down by the action of the jet 22. In this manner any possibility of pulling mudinto the vacuum pump 36 is eliminated. The rising mud level in the tank will also cause the second float 61 to contact and raise the float'30 even before the mud level reaches the latter, thus affording a more desirable, lower mud level in the tank.

As the that 61 falls toward the seats 64 on the outlet 20, the flow of mud drawn by jet 22 is reduced, thus reducing mud feed into the vacuum tank which in turn, reduces the action of the jet 22, correspondingly,

reducing the rate at which the mud is withdrawn from the tank. Therefore, the action of flow reduction is not entirely dependent on the float 61, but also on the operating efliciency of the jet 22. Conversely, as the float 61. rises, the rate of mud feed is increased and the jet 22 has a correspondingly greater efficiency to effect the mud withdrawal. 7

it will be apparent that only liquid mud should leave the vacuum tank outlet 20 regardless of how much vacuum is pulled by the jet 22. If the mud flow through the system should be so small as to pull dry because of the seats 64 holding the float 61 from forming a complete seal of the outlet 20, this would be of no consequence since drilling would not be in order with such a small volume of mud circulation. l

The advantages of this embodiment of the invention reside in the elimination of. the til-tube 21 which is expensive to build and to install. The elimination of this tube permits the de-gasser to be installed in positions which the presence of the U-tube otherwise would not permit. Moreover, the use of the float 61 on the mud outlet permits the use of greater variations of vacuum in pulling the mud into, through and from the tank 10. The amount of excess vacuum permissible with the U- tube 21 is governed by the length of the tube which, in turn, is governed by the vertical space available for installation. For instance, a seven foot U-tube with conventional twelve pound per gallon mud would permit a variation or excess of vacuum of only ten inches of mercury. It is easily possible to impose enough extra pull on the mud to suck the U-tube dry, pull gas over with the mud and defeat the purpose of the de-gasser. The float control 61 is not affected at all by any increased vacuum on the mud being pulled from the tank.

The hand lever 63 on the arm 62 may be used for manually actuating the float 61 for purposes of freeing the same of any dirt or debris accumulated on it or on the seats 64.

While in the foregoing there have been described and shown the preferred embodiments of the present invention, various modifications may become apparent to those skilled in the art to whichthe invention relates. Accordingly, it is not desired to limit the invention to this disclosure and various modifications may be resorted to, such as may lie'within the spirit and scope of the appended claims.

What is claimed as new is:

1. In a drilling mud de-gassing system, the combination of a mud de-gasser vacuum tank having a mud cascading means therein comprising inclined plates sloping downwardly toward the sides of the tank, and having a mud inlet conduit at one end and a mud outlet conduit at the other, trough means within the vacuum tank connected at one end to said mud inlet for supplying mud to the cascading plates, means for causing the flow of mud into, through and out of the mud de-gasser tank, comprising a jet nozzle discharging mud into the outlet conduit beyond the mud de-gasser; the improvement comprising means for regulating the vacuum imposed on the mud de-gasser tank comprising a manually controlled throttle valve provided in said mud intake conduit.

2. In an apparatus for continuously de-gassing drilling mud, comprising an inlet receptacle for mud to be treated,

connected with said gas ott'take pipe for creating a vacuuni within the de-gasser tank, and means for causing flow of mud into, through and out of said mud. de-gassing tank, comprising a jet nozzle for discharging mud into the outlet conduit beyond the de-gassing tank, the improve- 'ment which comprises means for controlling the vacuum in the tank, comprising a manually controlled throttle valve in the mud inlet conduit leading to the de-gasser tank.

3. In a drilling mud de-gassing system, the combination of an initial receptacle having an inlet for mud from a drilling well, a main mud de-gasser vacuum tank having a mud inlet pipe connecting the tank to the initial receptacle, an outlet for degassed mud leading from the degasser tank, and emergency means for initially separating excess gas from mud received from the well prior to its entry into the initial receptacle comprising an open bottomed mud-gas separator discharging into said receptacle and having at least one choke line discharging from the well into the upper portion of the initial separator and having a separate gas exit.

4. In a mud de-gassing system for drilling wells, including a preliminary receptacle for mud to be treated having a main mud inlet pipe leading from a drilling well, a main vacuum de-gasser tank having at one end a mud inlet conduit leading from the preliminary recep-.

tacle, and having an outlet for treated mud at the op posite end of the de-gasser tank; the improvement which comprises a preliminary separator for removing excess gas from mud, comprising an upright tank opening at its bottom into the preliminary mud receptacle for discharging mud thereinto, and having an inlet for gas laden mud entering the preliminary separator above the mud dis charge outlet, and having an outlet for discharging gas externally of the preliminary receptacle.

5. In amud de-gasser system, a mud de-gasser comprising a closed substantially cylindrical vacuum tank disposed with its axis in a substantially horizontal position and provided with a mud inlet at one end and having a sump therein provided with a longitudinally extending sloping bottom portion extending downwardly from the inlet end of the tank, a mud outlet for said tank, a mud trough separate from the sump underlying the mud degasser tank having a first mud receptacle at one end and a second mud receptacle at the other, the mud inlet to said vacuum tank communicating with said first mud re ceptacle and the mud outlet communicating with said second receptacle.

6. A mud de-gasser tank comprising a closed elongated horizontally disposed vacuum tank having a substantially level, horizontally disposed rnud overflow conduit extending lengthwise through the upper portion thereof, and means for supplying mud to be treated to one end of the conduit, said conduit being of substantially uniform cross sectional area throughout its length and having an elongated overflow slot in the upper portion thereof, said slot being relatively narrow adjacent the inlet end of the conduit, and widening toward the opposite end thereof.

7. A mud de-gasser comprising an elongated horizontally disposed vacuum tank, a horizontally disposed mud trough extending longitudinally through the upper portion of the tank, a mud inlet pipe for said de-gasser discharging into said trough adjacent one end thereof, said mud trough having an overflow slot in the upper portion thereof extending from end to end and being narrower at its inlet end and widening toward the opposite end thereof, downwardly and outwardly inclined mud cascading baffle plates on opposite sides of the trough and extending lengthwise thereof permitting mud to flow in thin streams to the bottom of the tank, a gas olftake pipe leading from the tank and connected to a source of suction, a sump in the bottom of the tank extending substantially parallel to the trough and having a bottom sloping downwardly from the inlet end of the tank to the opposite 7 end thereof, and a mud ofttake from degasified mud connected to the sump at the opposite end of the tank from the mud inlet. i

8. A mud de-gasser as set forth in claim 7, wherein an elongated gas vent pipe communicating with said gas offtake pipe is provided beneath the mud conduit and is ing a sloping bottom extending away from the inlet end of the tank, a mud outlet provided in the lower end portion of the sloping bottom of said sump, a float movable in said sump and coacting with said mud outlet to itself act as a throttle for mud through said mud outlet, a mud trough underlying the mud de-gasser tank having a first mud receptacle at one end and a second mud receptacle at the other, a mud inlet to said vacuum tank communicating with said first mud receptacle and a mud outlet in said sump communicating with said second receptacle.

r 10. The structure as defined in claim 9 together with manually operable means provided at the outside of said tank for actuating said float.

11. In a mud de-gasser system, a mud de-gasser comprising a closed substantially cylindrical vacuum tank 'disposed in a horizontal position and provided with a ,m'ud inlet in one end thereof, a longitudinally extending adapted for connection to a vacuum pump, a valve pro vided on said gas pick-up pipe, a float movable in said tank and operatively connected'to said valve, a second float movable in said sump and coacting with said mud outlet, said second float being disposed below the first mentioned float and being operatively engageable therewith, a mud trough underlying the mud de-gasser tank having a first mud receptacle at one end and a second mud receptacle at the other, a mud inlet to said vacuum tank communicating with said first mud receptacle and a mud outlet in said sump communicating with said second receptacle.

12. A mud de-gasser comprising a closed substantially cylindrical vacuum tank disposed in a horizontal position, a mud inlet provided in one end of said tank, a mud outlet'provided at the bottom of the other end of said tank, a mud overflow pipe connected to said mud inlet and extending longitudinally in the upper portion of said tank, a

tially in axial alignment with said mud overflow pipe,

said jet being adapted to deliver a stream of mud under pressure into the overflow pipe for flushing the same.

References Cited in the file of this patent UNITED STATES PATENTS 1,556,098 Gibson Oct. 6, 1925 1,758,566- Elliot May 13, 1930 1,897,398 Raymond Feb. 14, 1933 2,142,270 Vander Heust Jan. 3, 1939 2,241,273 Robinson et a1. May 6, 1941 2,243,176 Vander Heust -2 May 27, 1941 2,614,656 Clark et al. Oct. 21, 1952 2,622,694 Pryor Dec. 23, 1952 2,636,569 Smith Apr. 28, 1953 2,663,379 ,Doan Dec. 22, 1953 2,685,938 Walker et al. Aug. 10, 1954 2,714,308 Heck Aug. 2, 1955 

